Volume too low on AUX line in, coming out of laptop.

Ok, so I spent awhile looking around and didn't find a direct answer to my question.

I have a KENWOOD KDC-X991 headunit, JL 300/2 powering a set of CDT components. I am using a regular laptop as my carpc, and plugging it into the AUX IN port on the back of my headunit.

I noticed that if my volume is set to, lets say, 15 out of 38, that when I'm playing a CD it is MUCH louder and clearer than if I'm on my AUX-IN coming from my laptop. I would like to solve this problem.

I've also noticed that if you increase the volume up to around 20 out of 38 on the headunit, in AUX IN mode, a hiss/noise sound can be head in the background. You can hear this even if the laptop isnt plugged in. The only thing I can assume then is to obviously increase the volume coming out of the laptop, so I don't have to turn it up that high.

I'm connecting with a 1/8th in stereo cable from the laptop to the headunit. Is there anyway to fix this issue? Would buying a usb-soundcard for my laptop help? I don't believe it would fix the hiss-issue though, as you can hear it even if nothings plugged into the AUX.

I suppose I could increase the gain on my amplifier for AUX-mode, but then it would be out of wack for when I'm playing a cd.

go into your laptop's volume control (the volume slider panel that looks like this) panel and make sure the 'wave' volume and master volume are up all the way.

also check the your media player volume levels. for example, if you use winamp then you may see every volume slider in windows at 100%, but winamp's 'pre-amp' level might be only 50% (resulting in overall low volume output).